v1.0

This version reproduces the figures and results in following two papers:

Stanley, G.J., 2019a. Neutral surface topology. Ocean Modelling 138, 88–106. https://doi.org/10.1016/j.ocemod.2019.01.008

Stanley, G.J., 2019b. The exact geostrophic streamfunction for neutral surfaces. Ocean Modelling 138, 107–121. https://doi.org/10.1016/j.ocemod.2019.04.002